Mechanical clock movement with magnetic escapement

Abstract

A mechanical clock movement includes a resonator, an escapement linked to the resonator, and a display of at least one item of time information. The display is driven by a mechanical drive device via a counter wheel train, the work rate of which is set by the escapement. At least the resonator is housed in a chamber, in which a reduced pressure in relation to atmospheric pressure prevails. The escapement is a magnetic escapement including an escape wheel coupled directly or indirectly to the resonator via a non-contact magnetic coupling system, wherein the magnetic coupling system is formed so that a non-magnetic wall of the chamber runs through the magnetic escapement so that a first part of the escapement is located inside the chamber whereas a second part of the escapement is located outside the chamber.

Description

TECHNICAL FIELD[0001]The present invention relates to a mechanical clock movement equipped with a device for regulating its working formed by a resonator linked with an escapement. Escapement is understood in the clockmaking field to mean a system formed by a mechanism for maintaining oscillation of the resonator and a mechanism for counting this oscillation to set the work rate of a display of at least one item of time information. The resonator and the mechanism for maintaining its oscillation together define an oscillator. It will be noted that the mechanism for maintaining oscillation and the counting mechanism are formed by the very same mechanism for the distribution of energy supplied by a drive device, which perform both functions.[0002]More specifically, the present invention is concerned with increasing the quality factor of the regulator device in order to improve the working precision of the mechanical clock movement, in particular to improve the isochronism of the oscil...

AI Technical Summary

Benefits of technology

[0009]The aim of the present invention is to solve problems of the prior art in the case of watches equipped with a mechanical movement, in which it is provided to increase the quality factor of the oscillator by reducing vibrations due to air acting on the resonator. Moreover, the objective of the present invention is also to provide a mechanical watch that allows the chamber to also remain hermetically sealed during maintenance services, in particular when the oil traditionally provided on the bearings of various wheels must be renewed or a certain quantity of such an oil must simply be added to ensure correct lubrication of the wheels of the mechanical movement.

[0013]According to a preferred embodiment the mechanical movement does not have any wheel that pivots with a mechanical friction in the bearings in the hermetically sealed chamber. Thus, there is no need to supply oil to reduce the mechanical friction and to have a sliding friction with a film of oil. Therefore, firstly, no renewal of oil needs to be provided in the hermetically sealed chamber. Then, there is no risk of generating dust as a result of the pivoting movement of a wheel in the hole of a mechanical bearing. Moreover, this particular feature allows the working precision of the watch to be increased since the differences in working between various possible positions of the watch are minimised. Finally, such an embodiment also allows a reduction in the power necessary for maintaining the resonator and therefore for increasing the power reserve of the watch.

Problems solved by technology

In contrast, in the case of mechanical movements various significant problems have not enabled mechanical watches to be fabricated commercially with their movements each housed in a hermetic case, in which a reduced pressure prevails.

Firstly, mechanical watches generally have mechanical elements that pass through the case for the adjustment and / or operation of various functions, and this complicates the design of the case to enable this to ensure that a relatively stable reduced pressure is maintained over a long period.

Moreover, since the adjustment of the frequency of the resonator depends on the ambient pressure, this adjustment poses a manufacturing problem.

The solution comprising acting on an index using bimetallic blades by supplying an electric current or a light beam via the base of the case once the movement is encased and the low pressure has been established in particular poses a problem with respect to the precision of such an adjustment and a problem in the production process, since the individual adjustment of each watch must be done once the movement has been encased.

Hence, apart from a process that enables a particular device in the watch to be omitted in order to conduct the adjustment of the working thereof under reduced pressure, all the other problems remain.

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